On these Mr. Partington has the following note:--“The three last inventions may justly be considered as the most important of the whole ‘Century;’ and when united with the 68th article, they appear to suggest nearly all the data essential for the construction of a modern steam-engine. The noble author has furnished us with what he calls a definition of this engine; and although it is written in the same vague and empirical style which characterises a large portion of his ‘Inventions,’ it may yet be considered as affording additional proofs of the above important fact.” The Marquess’s “Definition” is exceedingly rare, as the only copy known to be extant is preserved in the British Museum. It is printed on a single sheet, without date, and appears to have been written for the purpose of procuring subscriptions in aid of a water company, then about to be established:-- “A stupendous, or a water-commanding engine, boundless for height or quantity, requiring no external nor even additional help or force, to be set or continued in motion, but what intrinsically is afforded from its own operation, nor yet the twentieth part thereof. And the engine consisteth of the following particulars:-- “A perfect counterpoise, for what quantity soever of water. “A perfect countervail, for what height soever it is to be brought unto. “A _primum mobile_, commanding both height and quantity, regulator-wise. “A vicegerent, or countervail, supplying the place, and performing the full force of man, wind, beast, or mill. “A helm, or stern, with bit and reins, wherewith any child may guide, order, and control the whole operation. “A particular magazine for water, according to the intended quantity or height of water. “An aqueduct, capable of any intended quantity or height of water. “A place for the original fountain, or river, to run into, and naturally, of its own accord, incorporate itself with the rising water, and at the very bottom of the aqueduct, though never so big or high. “By <g>Divine Providence</g> and heavenly inspiration, this is my stupendous water-commanding engine, boundless for height and quantity. “Whosoever is master of weight, is master of force; whosoever is master of water, is master of both; and, consequently, to him all forcible actions and achievements are easy.” “It is said,” continues our authority in another place, “that the Marquess, while confined in the Tower of London, was preparing some food in his apartment, (a singularly good result from a marquess having been obliged to be his own cook,) and the cover of the vessel having been closely fitted, was, by the expansion of the steam, suddenly forced off and driven up the chimney. This circumstance attracting his attention, led him to a train of thought, which terminated in the completion of his ‘water-commanding <g>engine</g>.’”